In hull construction, the bilge region is where the bottom shell meets the side shell. A strake is a continuous strip or plate along the hull, and the bilge strake specifically forms the corner at that junction. So the bilge strake is the corner plate of the hull where bottom and side meet around the bilge line. It’s not a deck strake (that would run along the deck), not the hull girder (the main longitudinal structural element), and not the forepeak plate (located in the forward tank area).

Official verification that repairs meet required standards is done by the classification society, an independent surveyor of ships. They conduct surveys after repairs—whether in port or in dry dock—to ensure the work complies with class rules, uses approved materials, and meets proper workmanship. Once satisfied, they endorse the vessel’s class status and renew or issue the relevant certificates and notations. The captain may supervise the repair work and the shipowner arranges it, but neither has the authority to certify that repairs are complete and up to class standards. The port authority may inspect for safety, but it does not certify repairs for class status.

Cargo surveys are used when there is higher risk or potential for discrepancy, such as with high-value or fragile cargo, dangerous goods, or suspected mis-declaration. In these situations surveyors verify what is actually on board by checking the quantity against the manifest, inspect the condition of the cargo and its packaging, and evaluate how it is secured and stowed to prevent movement during the voyage. For dangerous goods, they also confirm correct classification, packaging, labeling, segregation, and proper documentation in line with applicable regulations. This process helps protect against claims and insurance issues and supports safe transport. Routine, low-value shipments typically don’t require surveys, and surveyors don’t assess voyage speed or fuel efficiency, nor are surveys limited to imported goods or customs classifications.

Free surface effect happens when a space in the ship contains liquid or unsettled cargo that can move freely. As the vessel heels or rolls, the liquid surface or loose material shifts toward the low side, pulling the center of gravity downward and reducing the righting moment (GM). That makes the ship less stable and can worsen even small motions into larger angles of heel, especially in rough seas. The effect is strongest when tanks or holds are only partially filled and have enough open area for the contents to move. An example where it matters is a tanker or bulk carrier with partially filled cargo tanks or holds. If the ship encounters a turn or a heavy roll, the liquid or loose cargo can slosh from side to side, quickly changing trim and stability. To minimize the risk, fill tanks where possible or empty them, use internal baffles or multiple compartments to limit movement, segregate different liquids as needed, and secure or restrict cargo movement with proper dunnage and stowage.